Coin Based Mobile Charger

Hello friends, I am Anto... In this tutorial, we are going to develop the coin based mobile charger system.

The coin-based mobile battery charger developed in this paper is providing a unique service to the rural public where grid power is not available for partial/full daytime and a source of revenue for site providers. The coin-based mobile battery charger can be quickly and easily installed outside any business premises. The mobile phone market is a vast industry, and has spread into rural areas as an essential means of communication. While the urban population uses more sophisticated mobiles with good power batteries lasting for several days, the rural population buys the pre owned mobile phones that require charging frequently. Many times battery becomes flat in the middle of conversation particularly at inconvenient times when access to a standard charger isn't possible. The coin-based mobile battery chargers are designed to solve this problem.


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1) 89c51 microcontroller

2) 8051 development board

3) IR sensor

4) single channel relay

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Step 1: Gather the Required Components

I have used 8051 development board which have builtin power supply module like bridge rectifier, filter, +5v voltage regulator, +5v terminals, +12v terminals so that i can able to connect the external peripherals easily with the hardware. i can also interface the LCD on the development board without any breakout board

IR sensor to check the coin inside the coin box

single channel relay to switch the AC load to the mobile charger

LCD is used to display the charging timing..

89c51 Microcontroller

Step 2: Block Diagram and Circuit Diagram

I have designed the project according to the block diagram and the connection as per the circuit diagram.

8051 Micro controller is the heart of this project. The 8051 consists of 4 ports with 32 I/O pins. The data pins of the LCD are connected to the P2 of the micro-controller. The control pins of the LCD are connected to P3.2, P3.3 and P3.4 of the micro-controller. i have used switch instead of IR sensor in the circuit. but you have to connect the IR Sensor. The IR transmitter and IR receiver interfaced with lm358 comparator and then the output of the comparator is given to P1.0 of the microcontroller. I have connected the led to test the output in the proteus. But you have to interface the relay. The relay is connected through BC547 transistor and the base of the transistor is connected to P1.7 of the microcontroller.

Step 3: Making a Coin Box

Take a paper box and make a hole which a coin can be inserted. check the hole by inserting the coin in the hole. now place a IR sensor and tie it with the tag. now use jumper wires to connect the IR sensor to the hardware. close the box and use it as a coin box

Step 4: Program Code + Proteus Simulation

I have attached the attachment with the Embedded C code and proteus simulation of the exact hardware. test the code in simulation. make suitable editing if you needed. Convert the code using Keil uVision and download it using the programmer. Test the hardware.

Step 5: Result

Switch ON the hardware

Now you can view the heading of the project

now " Insert the coin will display"

so insert the coin in the coin box

You can observe the Relay switched ON automatically and the charging time will be shown on the LCD.

kindly connect a AC circuit to connect the mobile charger to the Relay to charge the mobile phones..

Thank you..

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